Electric connecting clamps



Feb. 6, 1962 c. COLEMAN ELECTRIC CONNECTING CLAMPS Filed April 11, 1958 J I 6 A 5 CONRAD COLL MAN BY M w ATTORNEYS 3,029,519 Patented Feb. 6, 1962 its , 3,629,519 ELEQTETQ CONNECTING CLAMZ S Qonrad @oiernan, l7 torgatan, Uddevaila, Sweden Filed Apr. 11, 1953, et. No. 727,92, M Claims priority, application Sweden Apr. 13, 19:37 2 Claims. (Ci. 339 273 The present invention relates to an improved electric connecting clamp or contact clamp, and particularly to a so-called earth or ground clamp as employed for connecting the return lead or cable of a welding generator or transformer to a metallic workpiece or structure. The contact clamp according to the invention comprises a pair of jaws and is principally char cterized by the feature that one jaw is provided at its rear end with means for guiding the other jaw longitudinally in a path forming an acute angle with said irst-mentioned jaw. To attach the clamp to the workpiece or the like, the movable jaw is pushed forward so as to cause both jaws to grip firmly the workpiece therebetween. The movable jaw will be retained in its gripping position by the frictional forces created by the reaction of the clamping force on the guiding means aforementioned.

The final tightening of the movable jaw on the workpiece is suitably efiected by giving a hammer blow against the rear end of the movable jaw. Said jaw therefore is given suflicient length to protrude somewhat backwards from the said guiding means so as to be accessible to a hammer. When the clamp is to be detached from the workpiece, a hammer blow conversely against the front end of the movable jaw will be sufficient to loosen the engagement.

Contact clamps according to the present invention have the practical advantage that they are simple and robust and comprise no threaded or other parts demanding an exact fit. Attachment to and detachment from the workpiece are carried out easily and swiftly. The clamp will provide a low electric contact resistance which is not impaired by vibrations or the like.

An embodiment of the invention is shown on the accompanying drawing wherein:

FIGURE 1 is a side view of the clamp partly in section;

FIGURE 2 is an end view of the clamp seen in the direction of the arrows II-ll in FIGURE 1; and

FIGURE 3 shows the clamp seen from the opposite end in the direction of the arrows III-III in FIGURE 1.

In the drawing, 1 denotes one of the clamp jaws. Said jaw 1 consists of a plate bent to the shape of an inverted channel the side walls of which are denoted by 2 and 3 and the flat channel bottom portion by 4, the latter being disposed at the top of the jaw. To the rear end of the jaw, where the bottom 4 of the channel is provided with an humped end portion 4a there are welded the end edges of the upwardly extending branches 6, 7 of a yoke 5 the fiat intermediate portion of which is denoted by 8. To the front edges of the yoke branches 6, 7 there is Welded a rectangular plate 9, the top edge of which is disposed at a distance from the intermediate portion 8 of the yoke, so as to form a rectangular-opening 10 above the top i 2 edge of the plate 9, and to the rear edges of the yoke branches 6, 7' there is welded a similar plate 351 the top edge of which being disposed at a distance from the middle portion 3 of the yoke so as to form a rectangular opening 12 above said top edge.

Together the openings 10 and 12 form a guide for the second jaw which is a slidable member 13 passing therethrough. The openings it and T2 are so disposed in relation to the fiat part 4 of the lower jaw ii that the slidable jaw 13 forms an acute angle with the said jaw 1 of the clamp. Adjacent to the front end of the slidable jaw 13 there is secured to it a pin 1 which prevents the jaw 13 from being Withdrawn through the opening iii. The slidable jaw 13, the rear end of which always protrudes rearwards through the opening 32, is provided with a bent front end portion 15 which is parallel to the clamp jaw 1. At the rear end of the jaw l the side Walls 2, 3 are interconnected by a fiat web 16 welded to said walls and converging toward the bottom portion 4. In the space between the plate 1.6 and the bottom portion 4 the electrically bare end portion 17 of the electric cable 18 is inserted. This end portion 17 is forced against the bottom portion 4 by means of a wedge 19 driven in between the plate 16 and the cable end portion 17.

It will be obvious that the clamp according to the invention can be used not only in connection with electric welding, but in all cases in which a large current has to be transmitted from a cable to a metallic object by means of a connecting clamp which can be applied and removed quickly and easily. a

I claim:

'1. A contact clamp comprising a jaw having a flat top portion, a support mounted on said jaw flat top portion and having a guide opening therethrough directed longitudinally of and on an acute angle toward said jaw flat top portion and a second jaw consisting of an elongated rod slidabiy mounted through said support opening for longitudinal movement to and from said jaw fiat top portion and having a bent end portion capable of cooperating with said jaw flat top portion for'clamping an object therebetween upon the other end of said second jaw being struck moving said second jaw towards said first-mentioned jaw.

2. A contact clamp as claimed in claim 1, wherein said second jaw has bent end portion adjacent said first jaw extends substantially parallel to said first-mentioned jaw fiat top portion.

References Cited in the file of this patent UNITED STATES PATENTS 1,332,442 Kane Mar. 2, 1920 1,566,153 McMunn Dec. 15, 1925 2,344,064 Sehueler Mar. 14, 1944 FOREIGN PATENTS 1 ,038,086 France Sept. 24, 1953 OTHER REFERENCES Every Man His Own Mechanic, FIG. 237, page 225, Ward, Lock and C0. 1884. 

